We will investigate the combined role of insulin, glucagon, prostaglandin synthesis & sulfur amino acid metabolism in the post-prandial calciuretic effect to protein (milk vs soy) vs carbohydrate ingestion. Postprandial urinary response to 3 test meals will be determined. The relationship between the degree of calciuresis & change in plasma glucagon, insulin, urinary prostaglandin metabolites & urinary sulfate excretion will be determined.